When leg parts are harvested from a carcass part of slaughtered poultry, e.g. from a back half of slaughtered poultry, the so called saddle of the carcass part remains. The saddle is generally speaking the part between the hip joints, optionally with a small piece of the lower back. The saddle has some meat attached to it, but this is hard to harvest, in particular hard to harvest in an automated way.
There has been a time when it was desired to harvest leg parts with as much skin and small, often ragged, meat parts attached to the legs as possible. The skin and small meat parts add to the weight of the leg parts, so leg parts could be sold at a relatively high price. In these type of methods, the ragged parts of meat and/or skin that remained attached to the leg parts after harvesting the leg parts are undefined and vary from leg part to leg part.
However, customer's desire has now changed to demanding leg parts that look good, are neatly trimmed and have no risk of bone splinters in them. This lead to the development of leg part harvesting machines that do an anatomic separation of the leg parts and the saddle. When doing an anatomic separation, body structures are separated from each other in such a way that the body structures themselves are kept intact as much as possible, rather than by cutting through the body structures. The anatomic separation involves dislocation of the hip joints.
For example, EP 0459580 describes such a method and system for anatomically separating leg parts from a saddle, e.g. starting from a back half. In the device and method of EP0459580, carcass parts such a back halves are brought to the device by an overhead conveyor that is provided with carriers. Each back half is suspended from a carrier; the carrier engages the back halves in the vicinity of the free ends of the leg parts.
When the back half has entered the device of EP0459580, a groin cut is made in the groin area between each leg part and the saddle. Then, a hip dislocating guide pushes the legs apart from each other. Due thereto, the leg parts become disengaged from the carrier of the overhead conveyor. The hip dislocating guide keeps on pushing the legs apart, to such an extent that the hip joints become dislocated and the leg parts come to hang down from the saddle instead of pointing upward, upward being their natural position.
A conveyor is provided in the device of EP0459580 that provides transport of the back halves when they are no longer carried by the carrier of the overhead conveyor. This conveyor engages the saddle.
After dislocation of the hip joints, an incision is made between each leg part and the saddle in the back region of the carcass part using a back cutter in such a way that after making the back incision, a tissue connection remains between the each leg part and the saddle part. The leg parts are therefore still connected to the saddle.
The back half is then conveyed further within the device by a spiked chain that engages the saddle. The back half is supported by a support guide during this movement.
Then, each leg part is gripped by a leg gripper. The leg gripper has a leg gripping slot for engaging a leg part and is moveable along a track that extends horizontally and parallel to the path followed by the saddle. Multiple leg grippers are mounted on an endless chain, of which the top flight runs parallel to the support guide for the saddle.
The leg grippers move at a higher velocity than the velocity at which the saddles are conveyed. So, when a leg gripper engages a leg part, the leg is moved faster than the saddles. This produces a pulling action that separates the leg parts from the saddle.
In the system and the method of EP0459580, the oysters are harvested together with the leg parts, which means that the oysters remain attached to the leg parts. The oysters are the parts of dark meat in the area where the legs are attached to the back meat in the vicinity of the spine. It is generally considered to be advantageous to harvest the oysters together with the leg parts.
On the other side of the leg, in the groin area, there is an other piece of meat present that can be worth harvesting. These pieces of meat (two per back half) are called “saddle meat parts”. These saddle meat parts comprise the oblique belly muscles (M. obliquus externus abdominis, M. obliquus internus abdominis) or parts thereof and/or muscle tissue in the direct vicinity thereof.
In current devices and methods for harvesting leg parts (e.g. as described in EP0459580) the saddle meat parts remain attached to the saddle. Often the saddle meat parts are thrown away with the saddle, or sometimes they harvested manually from the saddle. The manual harvesting of saddle meat parts is labour intensive and not very efficient.
However, the saddle meat parts are in themselves useful meat parts of rather good structure, so it is worth harvesting them. In particular in Asia, there now is a demand for those saddle meat parts, either separately or connected to the anatomically harvested leg parts.